Supporting rebar with interchangeable crowns

ABSTRACT

A support structure for retaining a reinforcing bar (“rebar”). Such a structure includes a rebar engaging portion, where the rebar engaging portion includes a receptacle. The receptacle includes a channel sized to receive the rebar, where the channel includes a first portion and a bar retaining portion defined by sidewalls that extend radially outward from a first end to a second end. The retaining features are disposed on the walls of the channel, where the sidewalls are configured to spread so that the rebar passes the retaining features and rests in the bar retaining portion as the rebar moves down the channel. Additionally, the support structure includes a support portion supporting the rebar engaging portion, where the support portion includes a plurality of legs which project outward from a central axis. In addition, the support structure includes a base configured to distribute weight of the support structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to the following commonly owned co-pending U.S. Patent Application:

Provisional Application Ser. No. 61/309,787, “System and Method of Supporting Rebar with Interchangeable Crowns,” filed Mar. 2, 2010, and claims the benefit of its earlier filing date under 35 U.S.C. §119(e).

TECHNICAL FIELD

The present invention relates to reinforcing bars (“rebars”) used in construction, and more particularly to retaining a rebar, a wire mesh, an electrical conduit, plumbing or other elongated bar in a desired configuration during construction.

BACKGROUND

Concrete is commonly used as a construction material because of its relatively low cost. Concrete is very strong in compression, but weak in tension. To increase the tensile strength of concrete, steel reinforcement bars (“rebars”) are added. For foundations, road work or other flat constructions, the rebar is often laid out in a grid pattern beneath the surface of the construction. To hold the rebar together in a grid, the bars are tied together where they intersect.

Various codes specify where the rebar must be placed. For example, the American Concrete Institute (ACI) in Section 318 of their code specifies that the rebar in a slab-on-grade foundation must be placed at the midpoint depth of the foundation. Thus, for example, in a four inch foundation slab, the rebar grid would normally be placed at a depth of approximately two inches. Consequently, the grid must be elevated off the ground to the desired position before concrete is poured. In many cases, concrete laborers use stones, pieces of broken bricks or materials to elevate the grid. This can cause the grid to be uneven or sag when the concrete is poured.

For concrete pillars and beams, the rebar is tied to a set of wooden frames and placed in a mold. The concrete is then poured into the mold to form the pillar, beam or other construction. However, this method suffers many disadvantages. First, it is difficult to align the rebar in parallel around the frames. Second, the frames often break or shift when the concrete is poured, causing the rebar to become misaligned. This reduces the tensile strength of the construction.

BRIEF SUMMARY

In one embodiment of the present invention, a support structure for retaining a reinforcing bar comprises a reinforcing bar engaging portion, where the reinforcing bar engaging portion comprises a receptacle to receive the reinforcing bar. The receptacle comprises a channel sized to receive the reinforcing bar, where the channel comprises a first portion and a bar retaining portion defined by sidewalls that extend radially outward from a first end to a second end. The retaining features are disposed on the walls of the channel, where the sidewalls are configured to spread so that the reinforcing bar passes the retaining features and rests in the bar retaining portion as the reinforcing bar moves down the channel. Additionally, the support structure comprises a support portion supporting the reinforcing bar engaging portion, where the support portion comprises a plurality of legs which project outward from a central axis. In addition, the support structure comprises a base configured to distribute weight of the support structure.

In another embodiment of the present invention, a support structure for retaining a wire mesh comprises a wire mesh engaging portion, where the wire mesh engaging portion comprises a receptacle to receive the wire mesh. The receptacle comprises a channel sized to receive the wire mesh, where the channel comprises a first portion and a bar retaining portion defined by sidewalls that extend radially outward from a first end to a second end. The retaining features are disposed on the walls of the channel, where the sidewalls are configured to spread so that the wire mesh passes the retaining features and rests in the bar retaining portion as the wire mesh moves down the channel. The support structure further comprises a support portion supporting the wire mesh engaging portion, where the support portion comprises a plurality of legs which project outward from a central axis. In addition, the support structure comprises a base configured to distribute weight of the support structure.

The foregoing has outlined rather generally the features and technical advantages of one or more embodiments of the present invention in order that the detailed description of the present invention that follows may be better understood. Additional features and advantages of the present invention will be described hereinafter which may form the subject of the claims of the present invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A better understanding of the present invention can be obtained when the following detailed description is considered in conjunction with the following drawings, in which:

FIGS. 1A and 1B illustrate a support structure for retaining a rebar in accordance with an embodiment of the present invention;

FIG. 2 illustrates a top view of the base illustrating the different positioning and sizes of the foot receptacles in accordance with an embodiment of the present invention;

FIG. 3 illustrates two embodiments of the crowns with feet inserted in the foot receptacles of the base in accordance with an embodiment of the present invention;

FIG. 4 illustrates a side view of one embodiment of the present invention of a crown;

FIGS. 5A-5E illustrate various embodiments of the present invention of snap fits;

FIGS. 6A-6D illustrate various embodiments of the present invention of a foot engaging a foot receptacle;

FIG. 7 illustrates a set of support structures supporting mats of bars in accordance with an embodiment of the present invention;

FIG. 8 illustrates additional views of a crown in accordance with an embodiment of the present invention;

FIGS. 9A-9C illustrate representations of one embodiment of the present invention of a portion of a support structure;

FIG. 10 illustrates an additional view of the base in accordance with an embodiment of the present invention;

FIG. 11 is a flowchart of a method for laying out rebar in accordance with an embodiment of the present invention; and

FIG. 12 illustrates a rebar support structure in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments described herein provide systems for retaining a rebar, a wire mesh, an electrical conduit, plumbing or other elongated bar in a desired configuration during construction. Embodiments described herein will be described primarily in the context of a rebar, but it should be understood that the embodiments are not limited to rebars and can be used to retain other types of bars.

FIGS. 1A and 1B are diagrammatic representations of one embodiment of the present invention of a support structure 100 for retaining a rebar. Support structure 100 can include a rebar engaging portion 102, a support portion 104 and a base 106. Support portion 104 and rebar engaging portion 102 can be formed of a single piece of material or they can be separate components that are coupled together while base 106 is a separate base. For purposes of this application, rebar engaging portion 102 and support portion 104 are referred to as a “crown” 107.

Support structure 100 can be formed of a suitable material, such as resilient plastic or other material, and can be manufactured to surpass requirements from the Uniform Building Code, International Building Code, American Concrete Institute, American Association of State Highway and Transportation Officials and standard practices as specified by the American Concrete Institute, the Concrete Reinforcing Steel Institute and other requirements. According to one embodiment, support structures 100 can be manufactured to have a capacity exceeding expected construction loads, which typically range between 250-300 pounds. Support structures 100, according to one embodiment of the present invention, can have a critical load in axial compression of 320 pounds or more. According to one embodiment, support structures 100 can have a critical load in axial compression of approximately 400 pounds. Other embodiments can have higher or lower critical loads as needed or desired. In one embodiment, support structure 100 can be configured so that it does not require ties or caps to retain the rebar.

Crown 107 can be used in a variety of applications for supporting the rebar in cement, including, but not limited to, foundations and cement beams. Rebar engaging portion 102 comprises one or more receptacles to receive the rebar. In the case of FIG. 1, engaging portion 102 includes paired bar receptacles 110 a and 110 b, bar receptacles 112 a and 112 b, bar receptacles 114 a and 114 b and bar receptacles 115 a and 115 b to receive the rebar. While eight bar receptacles are shown for the purposes of illustration, engaging portion 102 can include any number of bar receptacles that will fit to retain one or more pieces of rebar.

According to one embodiment, each set of paired receptacles can be sized to fit different sizes of rebar. In other embodiments, each set of paired receptacles can be sized to fit the same size of rebar. The depth of bar receptacles 110, 112 and 114 can be offset from each other so that the bars supported by engaging portion 102 can cross each other at the center of engaging portion 102. The bar receptacles of engaging portion 102 can be positioned so that the bars cross at a 90 degree angle or other desired angle. The bar receptacles can be snap-fit receptacles that allow a bar to be fully inserted by a human while inhibiting removal of the bar. The snap fit can provide feedback to the user so that the user knows when the bar has been sufficiently inserted and can result from the spring action of the bar receptacles.

Support portion 104 provides supports such as a plurality of leaves or legs 116 which project outward from a central axis and support rebar engaging portion 102. Support portion 104 can include any number of legs 116 or supports and the legs can have various configurations. Various embodiments of legs 116 are discussed below. Legs 116 can include feet 118 on which support portion 104 rests. According to one embodiment, each leg 116 can taper toward the respective foot 118 to leave area 120 open. This can allow concrete to flow beneath the legs 116 and between the feet 118.

Base 106 can be shaped to distribute weight. In the embodiment of FIG. 1, base 106 can be ring shaped, but in other embodiments, base 106 can include a solid disk, a rectangular shape or other shape. Base 106 includes foot receptacles 122 sized and positioned to receive feet 118. Foot receptacles 122 can be sized to form an interference fit with feet 118 to inhibit removal of base 106. In other embodiments, foot receptacles 122 and feet 118 may include a snap on fitting or feature that engages to inhibit removal of base 106. The snap-fit can close due to the spring action of foot receptacles 122 and can provide tactile or other feedback so that a user knows when a foot is properly engaged in foot receptacle 122. Foot receptacles 122 can be shaped so that there are no gaps between the walls of foot receptacles 122 and the corresponding feet 118, thereby reducing the likelihood of trapped air bubbles.

Additionally, base 106 can include foot receptacles 124. Foot receptacles 124 can be sized and positioned to receive the feet of a different sized crown 107. Thus, a single base can be made for use with interchangeable crowns 107.

Having a separate crown 107 and base 106 provides many advantages over existing systems. Crown 107 can be used in a number of applications with or without base 106 as needed or desired. Using crown 107 without base 106 provides advantages over prior art rebar chairs described in U.S. Pat. No. 6,282,860 (the “'860 patent”). When the rebar chairs of the '860 patent are used in the construction of concrete beams, the bases of the chairs will typically show through the side of the beam as large unsightly rings. This requires the beam to be painted or have another coating applied to hide the rings. Crowns 107 of the present disclosure, on the other hand, can be used without bases 106 and therefore will not leave exposed rings. In this case, if a portion of a crown 107 shows, it is only the bottom of the feet 118, which is a very small area. The same type of crown 107 can be used with base 106 in applications that require more stability or weight distribution, such as building over soft earth or sand. Thus, the same model of crown has different modes of operation.

FIG. 2 is a diagrammatic representation of a top view of base 106 illustrating the different positioning and sizes of foot receptacles 122 and 124 in accordance with an embodiment of the present invention. While eight foot receptacles 122 and 124 are illustrated, base 106 can include any number of receptacles. Additionally, while different receptacles are illustrated to accommodate different size crowns, a single type of foot receptacle can be used if the different sized crowns have the same leg configuration.

FIG. 3 is a diagrammatic representation of two embodiments of crowns 107 with feet 118 inserted in foot receptacles 122 or 124 of base 106 in accordance with an embodiment of the present invention.

FIG. 4 is a diagrammatic representation of a side view of one embodiment of the present invention of crown 107. Receptacle 110 a includes a channel 130 open to the top of crown 107 and sized to receive the rebar. Channel 130 can have a first portion 138 and a bar retaining portion 139 defined by sidewalls 132 that extend radially outward from a first end (e.g., more proximate to the center of crown 107) to a second end (e.g., the edge of crown 107). The base of channel 130 can be flat, curved or have another shape, but a curved shape increases the lateral elasticity of receptacle 110 a. Sidewalls 132 can angle so that the receptacle 110 a is wider at the opening than near the base of channel 130. Retaining features 137 can be disposed on the walls of channel 130. In one embodiment, retaining features 137 can be bumps or other features so that the width of the opening to bar retaining area 139 is smaller than the width of bar retaining area 139 or the rebar. In various embodiments, retaining features 137 can be formed based on the shape of sidewalls 132, can be projections that project inward from sidewall 132 or can be another feature that allows the rebar to enter rebar retaining area 139 due to the pressure of the rebar, but inhibit the rebar from leaving bar retaining area 139.

In operation, the rebar can be inserted in a first portion 138 of channel 130. As the rebar moves down channel 130, sidewalls 132 can spread slightly so that the rebar can pass bumps 137 and rest in bar retaining area 139 on base 141. According to one embodiment, bumps 137 snap over the bar to inhibit the bar from coming out of channel 130. The material, thickness or other properties of sidewalls 132 can be selected so that the rebar can be inserted manually.

FIG. 4 also illustrates another embodiment of a receptacle 115 b having channel 140 defined by sidewalls 142 and having retaining features 147. Rebar can be snapped into channel 140 and can rest in portion 143. For example, the rebar can rest on shoulders 144. Channel 140 can be open to an area 145 that has a curved shape to allow channel 140 greater lateral elasticity. This can allow channel 140 to better accommodate a range of rebar sizes.

The receptacles can be joined to each other by arms 143. According to one embodiment, the sidewalls of the receptacles and arms can be formed by a continuous, unitary shaped rib of material that projects radially outward from a first edge near the center of crown 107 to an outer edge. The rib can be laid out in an annular shape with an opening or gap between paired receptacles. Thus, each receptacle, according to one embodiment, does not extend to the base of the paired receptacle (e.g., the base 141 of receptacle 110 a does not extend across engaging portion 102 to the base of receptacle 110 b). Instead, there may be a gap between the paired receptacles at the center of crown 107.

FIGS. 5A-5E illustrate various embodiments of the present invention of snap fits. FIGS. 5A-5C include various embodiments of retaining features 137 including a tapered flange (FIG. 5A), rounded flange (FIG. 5B), a set of teeth (FIG. 5C) and a set of bumps (FIG. 5D). It should be noted that the embodiments of FIGS. 5A-5D are provided by way example. While each embodiment of FIGS. 5A-5D includes a taper or curve to ease insertion of the rebar, other embodiments of retaining features 137 can have other configurations. Retaining features may be disposed on both sidewalls or only one sidewall and multiple types of retaining features can be used. In one embodiment, the snap fit provided by a bar receptacle can be based, in part, on deformation of retaining features 137. In FIG. 5E, the rebar can enter the receptacle in a first direction and snap in a second direction.

FIGS. 6A-6D are diagrammatic representations of various embodiments of the present invention of a foot 118 engaging a foot receptacle 122. The retaining feature to retain foot 118 in receptacle 122 can be configured so that foot 118 cannot be removed without damaging receptacle 122 or foot 118 or can be configured so that foot 118 can be removed without causing damage if a threshold amount of force is applied. According to one embodiment, receptacle 122 can have sidewalls 148 that are sized to flex outward as foot 118 is inserted. Complementary engaging features on sidewalls 148 and foot 118 can engage to hold foot 118 in place. In FIG. 6A, foot 118 includes an indent 150 that engages a detent 152 on wall 148 of receptacle 122. The resiliency of walls 148 can hold detent 152 in indent 148 so that a threshold amount of force is required to disengage foot 118 from receptacle 122. In FIG. 6B, flanges 154 on walls 148 move over shoulders 156 on foot 118 to hold foot 118 in receptacle 122. In FIG. 6C, a tab 153 on foot 118 is received in a complementary receiver in sidewall 148. In FIG. 6D, bumps 157 fit over a portion of foot 118 to inhibit removal of foot 118. The examples of FIGS. 6A-6D are provided by way of example and other engaging features can be used. In other embodiments, foot 118 and sidewalls 148 can form an interference fit based on sizing. The foot receptacles can be snap-fit receptacles that provide feedback to the user so that the user knows when a foot has been fully inserted.

FIG. 7 is a diagrammatic representation of a set of support structures 100 supporting layers (referred to as “mats”) of bars in accordance with an embodiment of the present invention. A first set of support structures 100 can support a first mat 160 while a second set of support structures 100 can support a second mat 162 at a different height. While both mat 160 and mat 162 can be grids of rebar, in other embodiments, mat 160 can be a grid of rebar, while mat 162 includes plumbing, electrical conduit or other material. In some cases, a layer may include multiple types of rods (e.g., rebar and electrical conduit, plumbing and electrical conduit, etc.). Each support structure can use the same type of base 106, but use different crowns for different sizes of rebar, plumbing or other material. Concrete can be poured around the layers to create a construction.

FIG. 8 provides additional views of a crown 107 in accordance with an embodiment of the present invention.

FIGS. 9A-9C are diagrammatic representations of one embodiment of the present invention of a portion of support structure 104. FIG. 9A illustrates that legs 116 can taper upwards to create open area 120 between feet 118. In other embodiments, legs 116 can curve upwards (FIG. 9B) or have another profile to allow cement to fill between legs 116. In other embodiments, legs 116 do not extend inward to the center axis but only extend downward from the engaging portion 102 (FIG. 9C). Additionally, FIG. 9A illustrates that leg 116 can have holes 122 having a desired shape. The holes can be circular (FIG. 9A), diamond shaped (FIG. 9B), triangular (FIG. 9C), elliptical, rectangular, square or otherwise shaped.

FIG. 10 is a diagrammatic representation of another view of a base 106 in accordance with an embodiment of the present invention.

FIG. 11 is a flowchart of a method 1100 for laying out the rebar according to an embodiment of the present invention. A user can select a crown based on the size(s) of rebar being used, application, ordinances, construction practices or other factors (step 200). The user can also select the mode in which the crown will be used based on the application (step 202). This can include, for example, selecting whether to use the crown with or without the base. If the crown is being used in a wall or beam, the user may want to forego the base, whereas if the crown is being used in a foundation or slab, the user may want to use the base for added stability or weight distribution. The crowns with or without the bases can spaced as needed or desired (step 204). In some cases, the spacing of crowns is based on ordinances, standards or industry practices as to how often the rebar needs to be tied together. The following Table 1 provides example spacing for crowns. However, other spacing can be used as needed or desired:

Rebar Size Max Spacing ⅝ inch or #5 4 feet center-to-center ½ inch or #4 3 feet center-to-center ⅜ inch or #3 2 feet center-to-center ¼ inch or #2 2 feet center-to-center wire mesh 4 feet center-to-center

Rebar running in a first direction can be snapped into the crowns (step 206). If rebar running in another direction is to be used, the rebar can be snapped in the crowns in a second direction (step 208). The rebar running in the first direction may be at any angle as allowed by the crown up to 90 degrees from the rebar running in the second direction. If different sizes of rebar are used, the larger rebar is snapped in over the smaller rebar. However, in other embodiments, the smaller rebar can be snapped over the larger rebar. The steps of FIG. 11 can be repeated as needed or desired.

FIG. 12 illustrates another embodiment of the present invention of a rebar support structure 300 that includes a rebar engaging portion 302, a support portion 304 and a base 306. As described above, base 306 can be a detachable base so that base 306 can be used with various crowns 307. In the embodiment of FIG. 12, crown 307 includes a rebar receptacle 310 in which the rebar rests. The rebar is held in place by a cap 312. In other embodiments, removable base 306 can be used with rebar chairs in which the rebar is tied onto the chair.

While embodiments above have been discussed in the context of rebar, embodiments of the present application can be used with graphite tubing, glass tubing, plumbing, conduit, wire mesh, or any other elongated rod.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Additionally, any examples or illustrations given herein are not to be regarded in any way as restrictions on, limits to, or express definitions of, any term or terms with which they are utilized. Instead these examples or illustrations are to be regarded as being described with respect to one particular embodiment and as illustrative only. Those of ordinary skill in the art will appreciate that any term or terms with which these examples or illustrations are utilized encompass other embodiments as well as implementations and adaptations thereof which may or may not be given therewith or elsewhere in the specification and all such embodiments are intended to be included within the scope of that term or terms. Language designating such non-limiting examples and illustrations includes, but is not limited to: “for example,” “for instance,” “e.g.,” “in one embodiment,” and the like.

Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the disclosure. It is to be understood that the forms of the disclosure shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the disclosure may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Any dimensions provided are provided by way of example only and not limitation. Changes may be made in the elements described herein without departing from the spirit and scope of the disclosure. 

1. A support structure for retaining a reinforcing bar comprising: a reinforcing bar engaging portion, wherein said reinforcing bar engaging portion comprises a receptacle to receive said reinforcing bar, wherein said receptacle comprises a channel sized to receive said reinforcing bar, wherein said channel comprises a first portion and a bar retaining portion defined by sidewalls that extend radially outward from a first end to a second end, wherein retaining features are disposed on the walls of said channel, wherein said sidewalls are configured to spread so that said reinforcing bar passes said retaining features and rests in said bar retaining portion as said reinforcing bar moves down said channel; a support portion supporting said reinforcing bar engaging portion, wherein said support portion comprises a plurality of legs which project outward from a central axis; and a base configured to distribute weight of said support structure.
 2. The support structure as recited in claim 1, wherein said plurality of legs comprise feet on which said support portion rests.
 3. The support structure as recite din claim 2, wherein said base comprises foot receptacles to receive said feet.
 4. The support structure as recited in claim 3, wherein said foot receptacles are sized to form an interference fit with said feet to inhibit removal of said base.
 5. The support structure as recited in claim 3, wherein said foot receptacles and said feet comprise a snap-on fitting to inhibit removal of said base.
 6. The support structure as recited in claim 3, wherein said foot receptacles are shaped so that there are no gaps between the walls of said foot receptacles and said feet.
 7. The support structure as recited in claim 1, wherein each of said plurality of legs taper toward a respective foot to leave an area open thereby allowing concrete to flow beneath said plurality of legs and between each said respective foot.
 8. The support structure as recited in claim 1, wherein said base is ring shaped.
 9. A support structure for retaining a wire mesh comprising: a wire mesh engaging portion, wherein said wire mesh engaging portion comprises a receptacle to receive said wire mesh, wherein said receptacle comprises a channel sized to receive said wire mesh, wherein said channel comprises a first portion and a bar retaining portion defined by sidewalls that extend radially outward from a first end to a second end, wherein retaining features are disposed on the walls of said channel, wherein said sidewalls are configured to spread so that said wire mesh passes said retaining features and rests in said bar retaining portion as said wire mesh moves down said channel; a support portion supporting said wire mesh engaging portion, wherein said support portion comprises a plurality of legs which project outward from a central axis; and a base configured to distribute weight of said support structure. 